In this study the investigators want to look at whether using aspirin instead of rivaroxaban (after initial treatment with rivaroxaban) works as well at preventing blood clots while also reducing risk of bleeding and is more cost effective in patients who have either a total hip replacement or total knee replacement.

rivaroxaban 10mg x 9 days for total knee arthroplasty patients; x 30 days for total hip athroplasty patients

Drug: rivaroxaban and ASA

Experimental: ASA

ASA 81mg x 9 days for total knee arthroplasty patients; x 30 days for total hip athroplasty patients

Drug: rivaroxaban and ASA

Eligibility

Ages Eligible for Study:

18 Years and older

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria:

1. All patients undergoing elective total hip or knee arthroplasty at the participating institutions will be potentially eligible for this study

Exclusion Criteria:

Hip or lower limb fracture in the previous three months

Metastatic cancer

Life expectancy less than 6 months

History of major bleeding that in the judgment of the investigator precludes use of anticoagulant prophylaxis

History of aspirin allergy, active peptic ulcer disease or gastritis that in judgment of investigator precludes use of aspirin

History of significant hepatic disease or any other condition that in the judgement of the investigator precludes the use of rivaroxaban

Creatinine clearance less than 30 ml per minute

Platelet count less than 100 x 109 /L

Need for long-term anticoagulation due to a preexisting co-morbid condition or due to the development of venous thromboembolism following surgery but prior to randomization

Did not or will not receive rivaroxaban post-operatively for VTE prophylaxis

Bilateral total hip arthroplasty or simultaneous hip and knee arthroplasty

Major surgical procedure within the previous three months

Requirement for major surgery post arthroplasty within 90 day period

Chronic daily aspirin use with dose greater than 100 mg a day

Women of child bearing potential who are not abstinent or do not use appropriate contraception throughout the study drug period

Geographical inaccessibility for follow-up

Unwilling or unable to give consent

Previous participation in the study

Concomitant use with drugs that are strong inhibitors or inducers of both P-gp and CYP3A4

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01720108